Various types of power supply unit are known in the state of the art.
In the simplest case, the power supply unit includes a cavity in which a battery of rechargeable cells is placed in fixed manner. Such a battery of rechargeable cells is generally referred to as a "rechargeable battery pack" or as a "soft pack". The body of the apparatus includes a first power supply connector, and the battery of rechargeable cells includes a second connector. When the power supply unit is mounted on the body of the apparatus, the first and second connectors co-operate together so that the body of the apparatus (which contains in particular the transmit/receive means when the apparatus is a radiocommunications terminal) is powered by the battery.
When the battery is discharged, the user has two options. If the user does not need the portable apparatus immediately, the power supply unit can be left on the body of the apparatus, and the resulting assembly can be placed on a support for charging it via tabs provided for this purpose on the body of the portable apparatus (in general on its bottom end). In which case, the battery is recharged via the body of the portable apparatus
However, if the user does need the portable apparatus immediately, a new power supply unit whose battery is charged can be put in place. The battery of the replaced power supply unit can then be recharged directly by means of suitable charging equipment (instead of via the portable apparatus).
The major drawback with the above-mentioned solution is that it can be impossible for the user to use the portable apparatus. If the user has only one battery, and if that battery is discharged, then it is necessary to wait for the battery to be recharged before the portable apparatus can be used again. Furthermore, if the user has more than one battery, it is possible that, through inadvertence, all of them might be discharged at the same time. For example, this applies when the user puts a new power supply unit in place and then forgets to recharge the battery of the replaced unit.
In order to avoid such a situation which is very inconvenient for the user, a second type of power supply unit has been proposed. The principle of it is that the power supply unit can receive two types of power source, namely either a battery of rechargeable cells (which is then no longer fixed permanently in the cavity of the power supply unit), or a set of non-rechargeable cells. Thus, when no charged battery is available, it is possible for the user to use standard non-rechargeable cells instead of the battery of rechargeable cells. In general, a battery of rechargeable cells is replaced by three standard AA-type non-rechargeable cells. Since such non-rechargeable cells are readily available from a large number of shops, the user has operational apparatus available at all times.
As explained above, to enable the apparatus to be powered by the battery of rechargeable cells, it includes a second connector designed to co-operate with the first connector on the body of the portable apparatus. Therefore, when a set of non-rechargeable cells is used, it is also necessary to have available a connector serving as an electrical interface between the set of non-rechargeable cells and the first connector of the body of the portable apparatus.
The currently proposed solution consists in providing a removable additional part serving as said electrical interface between the set of non-rechargeable cells and the first connector of the body of the portable apparatus. The removable part includes a third connector designed to co-operate with the first connector.
In the current state of the art, the removable additional part is in the form of an independent housing made of plastic and that the user places in the power supply unit only when the set of non-rechargeable cells is to be used.
That solution is not very satisfactory because it means that the user must remember to keep the additional part on hand at all times. There is therefore a high probability that the part will not be on hand when the user actually needs it.
In addition, in its current form, the additional part has dimensions such that it can receive only small non-rechargeable cells. As a result, the length of operating time of the portable apparatus is reduced when non-rechargeable cells are used.